Liberapay is a recurrent donation platform, similar to Patreon, GoFundMe and other platforms. What makes it different is that LibreaPay is a non-profit organization and they fund themselves rather than charging transaction fees (though you will still get charged payment processing fees).
The source code for their platform is also open source. The code for Liberapay is available on Github.
What’s nice about Liberapay is that it’s easy to use, the transaction fees are non-existent and it gives users of free/open source software another platform on which to support developers. Recurring donations are sponsorships of a project. OpenCollective is a similar platform that we’ve covered before.